On Wednesday 20 February 2008 14:12, Robin Holt wrote: > For XPMEM, we do not currently allow file backed > mapping pages from being exported so we should never reach this condition. > It has been an issue since day 1. We have operated with that assumption > for 6 years and have not had issues with that assumption. The user of > xpmem is MPT and it controls the communication buffers so it is reasonable > to expect this type of behavior.
OK, that makes things simpler. So why can't you export a device from your xpmem driver, which can be mmap()ed to give out "anonymous" memory pages to be used for these communication buffers? I guess you may also want an "munmap/mprotect" callback, which we don't have in the kernel right now... but at least you could prototype it easily by having an ioctl to be called before munmapping or mprotecting (eg. the ioctl could prevent new TLB setup for the region, and shoot down existing ones). This is actually going to be much faster for you if you use any threaded applications, because you will be able to do all the shootdown round trips outside mmap_sem, and so you will be able to have other threads faulting and even mmap()ing / munmaping at the same time as the shootdown is happening. I guess there is some catch... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/